Such panels have already been fixed by means of collars formed around the tubes supported by and welded to the vertical tubes or beams, or by means of one-piece cradles between the tubes or the support beams and the tubes supported thereon or welded thereto, or by means of distance pieces or spaces formed in two parts which slide in each other, one of these parts being welded to the vertical tubes or beams, the other part being welded to the supported tubes.
Such fixing devices require careful preparation of the panel on a former and possibly a large number of welding operations. The connecting parts formed between the vertical tubes or beams and the horizontal tubes often include relatively small sections of contact with the horizontal tubes so that the sections are not properly cooled by the fluid which circulates in the horizontal tubes and that excessive thermal stresses may appear at the connection piece-to-tube link and cause breakage of the tube. Further, if there are vibrations in the panel of tubes during operation, stresses are concentrated at the rigid connections between the supported tubes and the support. This can cause breakage of tubes.
The present invention aims to remedy these drawbacks and to provide a device for fixing such panels of tubes which does not require very careful positioning of the tubes on a former, is simple and rapid to fix, requires pratically no welding operation and which allows the use of relatively simple intermediate parts which do not require very great manufacturing precision.